K 10
svn:author
V 7
glebius
K 8
svn:date
V 27
2011-04-04T07:45:08.930423Z
K 7
svn:log
V 520
When removing ifnets, we should first remove the reference to ifnet
from the interface index, then decrease refcount, not vice versa.

Otherwise there is a race (reproducible) when if_free_internal()
contests on IFNET_WLOCK(), and we got a zero-refed ifnet in the
index for a long time. It may be picked by some other thread,
that runs ifnet_byindex_ref(), who takes the ifnet from index,
and bumps refcount. When reader drops the lock, if_free_internal()
proceeds with free. Then reader tries to free it a second time.

END